Use /var/run/docker as root for execdriver

Signed-off-by: Alexander Morozov <lk4d4@docker.com>

daemon/daemon.go

@@ -1012,7 +1012,8 @@ func NewDaemonFromDirectory(config *Config, eng *engine.Engine) (*Daemon, error)
 	}
 
 	sysInfo := sysinfo.New(false)
-	ed, err := execdrivers.NewDriver(config.ExecDriver, config.Root, sysInitPath, sysInfo)
+	const runDir = "/var/run/docker"
+	ed, err := execdrivers.NewDriver(config.ExecDriver, runDir, sysInitPath, sysInfo)
 	if err != nil {
 		return nil, err
 	}

daemon/execdriver/native/driver.go

@@ -64,7 +64,6 @@ func NewDriver(root, initPath string) (*driver, error) {
 		root,
 		cgm,
 		libcontainer.InitPath(reexec.Self(), DriverName),
-		libcontainer.TmpfsRoot,
 	)
 	if err != nil {
 		return nil, err

integration-cli/docker_test_vars.go

@@ -17,11 +17,13 @@ var (
 	privateRegistryURL = "127.0.0.1:5000"
 
 	dockerBasePath       = "/var/lib/docker"
-	execDriverPath       = dockerBasePath + "/execdriver/native"
 	volumesConfigPath    = dockerBasePath + "/volumes"
 	volumesStoragePath   = dockerBasePath + "/vfs/dir"
 	containerStoragePath = dockerBasePath + "/containers"
 
+	runtimePath    = "/var/run/docker"
+	execDriverPath = runtimePath + "/execdriver/native"
+
 	workingDirectory string
 )